Drying apparatus



Oct. 9, 1934 H. E. DIETRICH DRYING APPARATUS 4 Sheets-Sheet 2 Filed Nov. 26, 1930 0ct. 9, 1934. H. E. DIETRICH DRYING APPARATUS 4 Sheets-Sheet 5 Filed Nov. 26, 1950 EaZ/exib?.

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55 lparatus embodying another formv of the invention.

Patented ct. 9, 1934 UNITED STATES PATENT OFFICE DRYENG APPARATUS Harold E. Dietrich, Chicago, Ill., assignor to rll`he Visking Corporation, Chicago, Ill., a corporation of Virginia Application November 26, 1930, Serial No. 498,462

18 Claims. (Cl. 34-48) The invention relates to drying apparatus, and Fig. 10 is a, fragmentary plan view of the more particularly to apparatus for drying celluapparatus shown in Fig. 9, and lose tubing, or sausage casings. Fig. 11 an enlarged section taken on line 11-11,

Cellulose tubes or sausage casings are formed of Fig. 10.

from viscose which is extruded through an an- Referring for the present to Figs. l to 8, inclu- 60 nular orifice to form a seamless tube. The tube sive, wherein one form of the invention is illusis subjected immediately to coagulating and retrated, the reference character designates generating baths, and is then washed in water. generally a housing to which heated air is sup- The Washed tube is preferably treated with a plied through a pipe 1l. The air is discharged 10 hygroscopic agent, after which it is dried. from the housing 10 through a pipe 12. 65

The primary object of the present invention As shown, the housing 10 comprises a top wall is to provide improved means for drying the cellu- 15, side walls 16, an end wall 18 at the entrance lose tubes or sausage casings, and a preferred end of 'the housing and an end wall 19 at the form of the invention is embodied in apparatus discharge end thereof. The vend walls 18 and 19 comprising a drier through which the tubing is are provided with alined apertures 20 and 2l, 70 advanced continuously. Means at the entrance respectively, through which cellulose tubing may and discharge ends of the drier are provided for be advanced to subject it to the heated air. The advancing the tubing through the drier and for tubing is shown at 23. retaining a bubble or quantity of air in that sec- Means iS prevded f01 advaneng the tubing 20 tion of tubing passing through the drier at any continuously through the housing 10- ThiS 75 given time. The air retained in the tubing exmeans preferably comprises a driven unit at pands it to a desired diameter during the drying the entrance end of the housingr and a driven unit operation. To insure that the tubing will be ex- 26 at the discharge end thereof. The driven unit panded to the proper diameter at all times, means 25 comprises a carriage 27 which is slidably jour- 25 is provided for displacing the advancing means naled on shafts 28 iixedinaframe-work 29 which 80 relative to each other so that they will increase eXtendS from 011e end 0f the apparatus t0 the or decrease the length of the column of air in other end thereof. Rotatably journaled in the the tube and thus decrease or increase, respeccarriage 27 are driven shafts 32 and 33 carrying tively, the diameter of the tube rolls 30 and 31, respectively. The shafts 32 and 30 Many other objects and advantages of the in- 33 are provided With beVel gears 34 and 35, Ie- 85 vention will become apparent as the following Spectively, meshing With bevel gears 36 and 37, detailed description progresses, reference being I'eSDeCtVelY, WhCh are SDlIled 1190!! a Shaft 40, had to the accompanying drawings, wherein; the shaft 40 being driven by means hereinafter Figure 1 is a, side elevation of drying apparatus described. The bevel gears 36 and 37 are conwhich embodies the invention. strained to move with the carriage 27 so that 90 Fig. 2 is a plarrview of the improved apparatus when the carriage is displaced along the shaft 28 Fig. 3 is an enlarged side elevation, partly in the bevel gears will be displaced in the same di` section, of the entrance end of the improved I'eCtiOIl alOIlg the Shaft 40, thereby retaining ppal-amg them in mesh with the bevel gears 34 and 35.

Fig. l is an enlarged side elevation, partly in dllnzus andtlftngmlyhsppot 95 ani erro xe oasa W1C asis section' of the dlscha'rge end of the Improved ends rotatably journaled in slides 44. Suitable apparatus.

means, similar to `those hereinafter described 1n OEg' 521s an enlarged Sectlon taken on Ime 5 5 connection with the driven unit 26, are provided g' for displacing the slides 44 to bring the roll 42 100 F1g'-6 1S a dem@ Vlew of a' bcake band and into and out -of engagement with the rolls 30 and n actuating mechanism therefor which form a part 31. These means for raising and lowering the of the improved apparatus. a slides 44 comprise a handle 45 whereby they may Fig. 7 is a central longitudinal section through be manually actuated 5G a dierential device OTmS a part Of the The driven comprises a Carriage mpIOi/ed apparatusslidably journaled upon shafts 5l which are fixed Fig. 8 is a diagram of an electrical circuit formin the framework 29. Rotatably journaled in ing part of the improved apparatus. the carriage are shafts 53 and 54 which carry Fig. 9 is a fragmentary side elevation o apdriven rolls 55 and 56, respectively. Bevel gears 58 and 59 are fixed to the shafts 53 and 511i, re- 110 spectively, and mesh with bevel gears and 61, respectively. The bevel gears 60 and 61 are splined upon a shaft 40al and are constrained to move with the carriage 50 when it slides in either direction upon the shafts 5l. Normally supported by the rolls 55 and 56 is an idler roll 64 which is carried by a shaft 65. The ends of the shaft are rotatably journaled in splines 66 journaled in the carriage 50 (see Fig. 5). A shaft 67 rotatably journaled in the carriage 50 carries eccentrics 68 disposed in apertures 69 provided in the slides 66, the construction being such that the shafts 67 and the eccentrics 68 may be rotated to raise or lower the slides. The means for rotating the shaft 67 and the eccentrics 68 comprises a handle 70 which may be manipulated by the operator of the apparatus.

The carriage 50 is yieldingly urged to the right (Figs. 1, 2 and 4) by a weight 72 secured to one end of a cable 73 which has its other end secured to the carriage 50, the cable being threaded over a sheave 74 rotatably journaled in the framework 29. Thepurpose of this construction will presently appear.

As best shown in Figs. 3 and 4, the cellulose tubing 23 is delivered to the drying apparatus over a roller 76 rotatably journaled in the framework 29. From the roller 76 the tubing passes over the rollers 30 and 31 and under the idler roll 42. The tubing then passes through the housing 10' and over the rolls 55 and 56 and under the idler roll 64, the dried tubing being discharged from the apparatus on a chute 78. The idler rolls 42 and 64 are lowered to rest upon the rolls 30-31 and the rolls 55-56, respectively, and they co-operate with the driven rolls to advance the tubing. The driven rolls and the idler rolls also co-operate to retain a bubble or quantity of air in that section of the tubing which is passing through the housing 10 at any given time.

The means for driving the shafts 40 and 40a comprises an electric motor 80 positioned at the discharge end of the housing 10. Suitable reduction gearing (not shown) within the housing of the motor drives a shaft 81 to which a sprocket gear 82 is fixed. Meshing with the sprocket gear 82 is a sprocket chain 83 which meshes with a sprocket gear 84 xed to the shaft 40a. The shaft 40a is rotatably journaled in the framework 29 and is provided with a bevel gear 86 at one of its ends, the bevel gear 86 being constrained to rotate with the shaft 40a and forming a part of a differential device which is designated generally by the reference character 87. The axes of rotation of the shafts 40 and 40a are co-incident and the inner end of the shaft 40 has a bevel gear 88 secured to it, which bevel gear is disposed in opposite relation with` the gear 86 and is identical therewith in size.

Meshing with the gears 86 and 88 are pinions 89 and 90 which are rotatably journaled in a housing member 91 provided with hollow trunnions 92 and 93. The hollow trunnion 93 is rotatably journaled upon the adjacent end of the shaft 40a and the hollow trunnion 92 is rotatably journaled upon the adjacent end of the shaft 40. Fixed to the trunnion 93 is a gear 94 which meshes with a gear 95 fixed to a shaft 96 which is rotatably journaled in the framework 29. A brake drum 98 constrained to rotatewith the trunnion 92 is rigidly secured to the gear 94 by a housing member 99. A brake band 100 disposed around the brake drum 98 is frictionally engageable therewith and mav be actuated by means comprising a cam 101 disposed between the ends of the band. A compression spring 102 urges the brake .band into frictional engagement with the brake drum 98, the spring being mounted upon a rod 103 which projects through the ends of the brake band. A strut 105 carried by the framework 29 prevents the brake band from rotating around the co-incident axes of the shafts 40 and 40a.

The construction of the differential 87 is such that, when the brake drum 98 is held against rotation, the shaft 40 is driven at the same speed as the shaft 40a, but when the brake band 100 is expanded so that the brake drum 98 may revolve, the shaft 40 is driven either faster or slower than the shaft 48, the speed of the shaft 40 depending upon the direction in which the gear 94 is driven by the gear 95, as will presently appear.

The cam member 101 is secured to one end of a lever 110 which has its other end secured to a crank lever 111, the other end of the crank lever 111 being pivoted to one end of a rod 112 which is slidably journaled in the framework 29. The other end of the rod 112 has an armature 113 secured thereto, which armature 113 is controlled by a magnet 114. The magnet 114 is carried by a U-shaped bracket 115 mounted upon the framework 29. Disposed around the rod 112 and interposed between the framework 29 and a washer 116, secured to the rod 112, is a compression sp1'ing117 which yieldingly urges the rod 112 to the left (Figs. 3 and 4) to hold the cam member 101 in a position wherein it permits the brake band 100 to effectively engage the brake drum 98.

A sleeve 120 is screw-threaded upon one endo'f the shaft 96 and is rigidly secured to the carriage 27 (see Fig. 3). The construction is such that when the shaft 96 is rotated, the carriage 27wll be displaced toward or away from the entrance end of the housing 10, the direction in which the carriage 27 is displaced being determined by the direction of rotation of the shaft 96. The means for rotating the shaft 96 comprises a sprocket gear 122 which is fixed to and meshes with a sprocket chain 123. The sprocket chain 122 meshes with a sprocket wheel 124 fixed to a shaft 125 which is operatively connected through reduction gearing (not shown) to the shaft (not shown) of a reversible electric motor 126.

'I'he direction of rotation of the motor 126 is controlled by means which is responsive to any changes in the diameter of the tube 23, it being understood that that section of the tube passing through the housing 101 is inflated. The means responsive to changes in diameter of the tube preferably comprises rollers 130, 131 and 132 which are rotatably journaled upon pins 133 projecting from a bracket 134 which is rigidly secured to the framework 29. As best shown in Fig. 3, the tubing 23 passes over the rollers 130, 131 and 132 which are alined horizontally. Engaging the upper side of the tube 23 is a roller 135 rotatably journaled on the lower end of a lever 136 which is pivoted intermediate its ends upon a pin 137. The upper end of the lever 136 is provided with contact members` 140 and 151. The contact member 140 is engageable with contact members 142 and 143 which are engageable, in turn, with contact members 144 and 145, respectively. The construction is such that when the contact member 140 engages the contact members 142 and 143, the contact members 142 and 143 engage the contact members 144 and 145, respectively. The contact 141 is engageable with contact members 147 and 148 and is adapted to depress them into engagement with contact members 149 and 150, respectively. The several contact members are connected in an electrical circuit which includes the magnet 114 and eld or armature windings (not shown) in the motor 126 (see Fig. 8). The electric circuit is connected to any suitable source of electrical energy, and the construction is such that if the contact member 140 engages the contact members 142 and 143 bringing them into engagement with the contact members 144 and 145, respectively, the motor will rotate in a predetermined direction and the magnet 11e will attract its armature 113. If the contact member 141 engages the contact members 147 and 184 and causes them to engage the contact members 149 and 150, respectively, the motor 126 is driven in the'opposite directionl and the armature 113 is attracted by the magnet 114.

The rollers 130, 131, 132 and 135 are mounted in such manner that when the axis of rotation of the roller 135 is disposed in the same vertical plane as the axis of rotation of the roller 131, the distance between them is equal to the diameter to which the tubing 23 should be inflated. lin the event the tubing decreases in diameter, due to loss of air from it, the roller 135 will swing tcward the roller 433, and if sumcient air escapes from the tubing 23, the contact member 141 will engage the contact members 11e-'i and 148 and bring them into contact with the contact members 1419 and 15u, respectively. rIihis will cause the magnet 114-to become energized so that the brake band 106 will be released. The motor 126 will rotate the shaft 96 so that the carriage 27 will be advanced toward the carriage to diminish the distance between them. This displacement of the carriage 2'? will, of course, cause the tube 23 to increase in diameter to return the roller 135 into the position wherein it is shown in Fig. 3, whereupon the motor 126 ceases to operate and the magnet 111i is de-energized so that the brake band effectively engages the brake drum 98 again.

1f, for any reason, the tube 23 increases in dil ameter, to an undesirable extent, the contact member 140 will engage the contact members 142v and 1413 and bring them'into engagement with the contact members ldd and 1115, respectively, so that the brake band 100 will be released and the motor 126 will operate to displace the carriage 27 away from the carriage 50, the rate of feed at carriage 2'! being increased at thesame time, whereupon the tubing 23 will decrease in diameter until the contact 141 is disengaged from the contact members 1d? and 143. The brake band 10G will then engage the brake drum 38 eectively and the motor 126 will stop.

1t is understood that the apparatus (not shown) which forms the tubing 23 is preferably of the type which operates continuously. When the drying apparatus is to be set in operation, the forward end of the tubing 23 is threaded through the apparatus in the manner illustrated ln the drawings, the rolls 12 and 6d being first lifted out of contact with the driven rolls which normally support them. After the tubing has been threaded through the apparatus, the roll d2 is lowered to clamp the tubing between it and the rolls 3G and 31. Air under relatively low pressure is then introduced into the forward end of the tubing to inflate it, and when it has been inflated to the correct diameter, the roll 6d is lowered into engagement with the rolls 55 and 56, whereupon a bubble of air is confined or retained in that section of the tube which is disposed between the driven units 25 and 26. The motor 80 is then started, whereupon the tubing 23 is advanced continuously through the housing 10 and the motor 126 operates automatically to hold the tubing inflated to a predetermined diameter. The tubing is advanced through the housing 10 at a speed which permits it to be dried to a predetermined extent by the heated air circulated through the housing. n

The weight 72 operatively connected to the carriage 50 tends to displace the carriage 50 away from the carriage 27 and, therefore, holds the tubing 23 under a constant tension.

It will be readily understood that after the brake band 100 is released and the shaft 96 is rotated through the medium of the motor 126, the gear will rotate the gear 9d and it, in turn, will rotate the housing member 91 in the direction the shafts 40 and 40a rotate, or in the opposite direction, the direction the housing member 91 is rotated being determined by the direction in which the shaft 96 is rotated by the motor 126 to advance or retract the driven unit 25. The construction is such that when the driven unit 25 is advanced toward the driven unit 26 to diminish the length of the tubing extending between these driven units, the shaft e0 will be driven at a slower speed than the shaft 40a', so that the rolls 30 and 31 will be driven at a slower speed than the rolls 55 and 56. When the driven unit 25 is displaced in a direction away from the driven unit 26, the shaft 40 will be driven at a speed greater than at the speed the shaft 46a is rotated, and the rolls 30 and 31 will rotate at a speed greater than the speed at which the rolls 55 and 56 are rotated.

ln some instances, I may prefer to omit automatic means for displacing the driven unit 25 relative to the driven unit 26, as the shaft may be rotated manually to advance or retract the driven unit 25. Therefore, the appended claims are not limited to automatic means for such displacement of the driven unit 25 relative to the .the machine illustrated in Figs. 9 to 11, inclusive,

comprises a driven unit 26e at the discharge end of a drier housing 10c. The driven unit 26e is substantially identical in construction with the driven unit 26, described above, and the apparatus disposed within the housing 10cand in advance of it (not shown) is substantially identical with the apparatus disposed in and in advance of the housing 10.

In place of the shaft 40a, which is employed in the apparatus shown in Figs. 1 to 8, inclusive, two shafts dOc and 40d are employed, the shaft 10c being driven through a sprocket chain83c by an electric motor 80e. The shaft lfille drives differential gearing 97e which is identical with the differential gearing 87 described above and has the same function. The shaft 40e drives the shaft 40d through a means including a sprocket chain 200. The shaft 40d is splined and has the same function as theright-hand end (Fig. A.) of the shaft 10a to drive rolls 55o and 56e, which rollers carry an idler roll 64o. The rolls 55e, 56e and 64o are substantially identical with, and

ies

have `the same functions as the rolls 55, 56 and 64, respectively, described above, and they are rotatably journaled in the driven unit 26o which is yieldingly urged to the right (Fig. 9) by the weight 72C. Means including a lever 70o is provided for raising the roll 64o so that the cellulose tubing may be threaded through the apparatus. A discharge aperture 21e is provided in the housing 10 (see Fig. 11) and this discharge aperture is below the axes of the rolls 55e and 56C. Carried by the driven unit 26C is a plate 201 which carries a plate 202, U-shaped ystrips 203 being provided to secure the plate 202 to the plate 201. The plates 201 and 202 converge to- Ward the driven unit 26c and are disposed so that the tubing 23 will pass between them as it passes through the aperture 21o, the plates being adapted to flatten the tubing 23. At the discharge end of the plate 202 a roller 206 is provided, over which rollers the attened tubing rides as it passes to the roll 55o. In the preferred embodiment of the invention, the roller 206 is in relatively close proximity to the roll 55e so that the tubing will be retained in its flattened condition as it is fed onto the roll 55e.

Obviously, the plates 201 and 202 and the roller 206 are constrained to move bodily with the unit 26e when the latter is displaced by the weight 72o or against the action of this weight. In practice, the construction shown in Figs. 9 to 11, inclusive, has been found exceedingly advantageous, for when the tubing 23 is fed directly onto the roll 55 in a fully inflated condition,

. there is a tendency of the tubing to bunch as it passes between the idler roll 64 and the driven rolls 55 and 56, the result of such bunching being the loss of air from the bubble thereof coniined in the tubing.

The term air is employed in a broad sense in the appended claims and includes gaseous mediums of every kind and description.

While I have shown and described certain Vembodiments of my invention, it is to be understood that it is capable of many modifications. Changes, therefore, in the construction and arrangement may be made without departing from the spirit and scope of the invention as disclosed in the appended claims, in which it is my intention to claim all novelty inherent in my invention as broadly as possible, in view of the prior art.

What I claim as new, and desire to secure by Letters Patent is:

1. In apparatus of the kind described, a housing, a plurality of means for advancing tubing through the housing and for retaining a bubble of air in that section of`the tubing disposed between the advancing means, and means controlled by the diameter of the tubing for displacing one of said advancing means relative to the'othe..

2. In apparatus of the kind described, a housing, a plurality of means for advancing tubing through the housing and for retaining a bubble of air in that section of the tubing disposed between the advancing means, and means responsive to changes in the diameter of said tubing and including electrically operated mechanism for displacing one of said advancing means relative to the other.

3. In apparatus of the kind described, a housing, a plurality of means for advancing tubing through the housingand for retaining a bubble of air in that section of the tubing disposed between the advancing means, a plurality of rollers engaging said tubing, and means controlled by Said rollers for displacing one of said advancing means relative to the other.

4. In apparatus of the kind described, a housing, a plurality of means for advancing tubing through the housing and for retaining a bubble of air in that section of the tubing disposed between the advancing means, a movable member engaging said tubing intermediate said advancing means, and electrically operated mechanism controlled by said movable member for displacing one of said advancing means relative to the other.

5. In apparatus of the kind described comprising a plurality of means disposed at opposite ends of said housing for advancing a flexible tubing therethrough and for retaining a bubble o air in that section of the tubing which extends between them, means for displacing one of said advancing means as a unit relative to each other, means for actuating one of said advancing means, and means including diiierential gearing whereby said actuating means actuates the other of said advancing means.

6. In apparatus of the kind described, a housing, means including a pair of rolls at one end of the housing for advancing flexible tubing therethrough, means including a second pair of rolls at the other end of said housing for advancing said tubing therethrough, the iirst mentioned pair of rolls and a second pair of rolls being adapted to retain a bubble of air in that section of the tubing disposed between them, means for displacing one of said pairs of rolls away from or toward the other, means for driving one roll of said second pair of rolls, and means including differential gearing for operatively connecting sad driven means to one of the iirst mentioned pair of rolls.

7. In apparatus of the kind described, a housing, means including pair of rolls at one end of the housing for advancing iiexible tubing therethrough, means including a second pair of rolls at the other end of said housing for advancing said tubing therethrough, the first mentioned pair of rolls and said second pair of rolls being adapted to retain a bubble of air in that section of the tubing disposed between them, means including means responsive to changes in the diameter of the tubing for displacing one of said pairs of rolls away from or toward the other, means for driving one roll of said second pair of rolls, and means including differential gearing for operatively' connecting said driven means to one of the first mentioned pair o f rolls.

8. In apparatus of the kind described, a housing, a pair of rolls at one end of said housing for advancing a tube therethrough, a second pair of rolls disposed at opposite ends of the housing for advancing said tubing therethrough, the rst mentioned pair of rolls and said second pair of rolls being adapted to retain a bubble of air in that section of the tubing extending between them, means for displacing one of said pairs of rolls away from or toward the other to increase or decrease the length of tubing extending between them, means for driving one of a second pair of rolls, and means including differential gearing and brake mechanism for operatively connecting said driving means to one roll of the first mentioned pair of rolls.

9. In apparatus of the kind described, a housing, a pair of rolls at one end of said housing for advancing a tube therethrough, a second pair of rolls disposed at opposite ends of the housing for advancing said tubing therethrough, the iirst mentioned pair of rolls and said second pair of rolls being adapted to retain a bubble of air in that section of the tubing extending between them, means including means responsive to the diameter of the tubing for displacing one of said pairs of rolls away from or toward the other to increase or decrease the length of tubing extending between them, means for driving one of a second pair of rolls, and means including diierential gearing and brake mechanism for operatively connecting said driving means to one roll of the first mentioned pair of rolls.

10. In apparatus of the kind described, a housing, a plurality of spaced means for advancing tubing through said housing and for retaining a bubble of air through a section of the tubing extending between them, means for displacing one of said advancing means relative to the other to increase or decrease the length of the tubing extending between them, and means yieldingly urging one of said advancing means in a direction away from the other to tension the section of tubing extending between them.

11. In apparatus of the kind described, a housing, a plurality of spaced means for advancing tubing through said housing and for retaining a bubble of air through a section of the, tubing extending between them, means including means responsive to changes in diameter of the section of tubing extending between said advancing means for displacing one of said advancing means relative to the other to increase jor decrease the length of the tubing extending between them, and means yieldingly urging one of said advancing means in a direction away from the other to tension the section of tubing extending between them.

12. In apparatus of the kind described, a housing, a plurality of means for advancing tubing through the housing and for, retaining a bubble of air in that section of thetubing disposed between the advancing means, and means for varying the distance between one of said advancing means relative to the other to vary the length of tubing inflated by said bubble.

13. In apparatus of the kind described, a drying chamber, and a plurality of means disposed at opposite ends of said drying chamber for retaining an isolated bubble of air in the section of tubing extending between said plurality of means, one'of said plurality of means being adapted to advance the tubing and one of said plurality of means being movable away from or toward the other` to vary the diameter of the tubing extending between said plurality of means.

14. In apparatus of the character set forth: a housing through which a continuous length of tubing is fed; means for progressively squeezing an entrapped isolated bubble of air into that portion of the tubing which lies within said housing, comprising a driven unit at one end of the housing, a second driven unit at the other end of said housing, and means for Varying the distance between said units comprising a. rotatable screw-shaft making screw-threaded engagement with the rst mentioned driven unit.

15. In apparatus of the character set forth: a housing through which a continuous length of tubing is fed; means for entrapping an isolated bubble of air in that portion of the tubing which is passing through saidP housing comprising squeezer-means near the entrance to said housing and means for squeezing and withdrawing said tubing at the exit to said housing; and means for regulating the distance between the squeezer-means at the entrance and the squeezing and advancing meansat the exit to said housing.

16. In apparatus of the character set forth: a housing through which a, continuous length of tubing is fed; means for entrapping an isolated bubble of air in that portion of the tubing which is passing through said housing comprising a driven presser-roll unit near the entrance tov said housing, and a presser-roll unit at the exit to said housing; means for urging the unit at one end'of the casing away from the unit at the other end so as to exert a constant tension on the tubing between said units; and means for driving the rolls in one unit faster than the rolls of the other to vary the length of tubing therebetween.

17. Mechanism as set forth in claim 16, in

which the means for driving 'the rolls in one unit faster than the other comprises a diierential gear-unit through which one set of rolls are driven from the other, and mechanism for rotating the differential-gear unit to provide the desired difference in speed.

18. Mechanism as set 'forth in claim 16, in which the means for driving one unit faster than the other comprises .a double-throw reversing switch having an operating arm in engagement with the tubing and automatically controlled by the diameter of the tubing.

HAROLD E. DIETRICH. 

